Containers

ABSTRACT

A method of making a succession of food or beverage containers each comprising a vessel having a mouth surrounded by a rim presenting an upper surface of plastics material. The method comprises filling each vessel in turn and feeding over the vessel a continuous composite web of lidding material produced by forming spaced apart perforations, each comprising at least one through hole, in a continuous first web of diaphragm material having a plastics surface weldable to the vessel rim. The method also comprises forming spaced apart pull tabs in a continuous second web of peel strip material by folding each of a succession of portions of the second web against itself to form each pull tab and subsequently applying and peelably securing the second web which is narrower than the first web to the first web so as to obturate the perforations such that one pull tab is situated adjacent each perforation and remains secured to the second web only at a junction on its one end. Moreover, the method comprises cutting a lid from the web and securing the lid by an endless peripheral weld to the upper surface of the rim thereby closing the vessel.

This invention relates to containers for foodstuffs and beveragescomprising a container body at least the inner surface of which is ofplastics material, especially though not exclusively those in which suchproducts are sold for consumption direct from the container itself; tomethods of making such containers and to apparatus for performing suchmethods.

A method of packaging for foodstuffs and beverages that is becomingincreasingly common is that known as aseptic packaging. Conventionalcanning and bottling processes rely on the application of heat to theproduct, in its hermetically-sealed can or other container, in order toachieve the degree of sterilization (pasteurisation) needed to ensurethe survival of the product, in a usable condition at ambienttemperatures, for a sufficient length of time. Aseptic packagingprocesses are those which, instead of relying on the application ofheat, achieve this end result by ensuring that the product is, at thetime of being packaged, not contaminated by any undesirable or harmfulorganisms or spores, and that it is packed in a container of which allthe components are sterilised to a commercially-acceptable degree, andremain so until they have been hermetically sealed with the productinside. Aseptic packaging is suitable for any product which is capableof surviving in a usable condition for a satisfactorily long, butpredetermined, period of time in a hermetically sealed container (i.e.without deteriorating due to its own inherent characteristics).

While a wide variety of containers can be used for aseptic packaging,including metal cans, the absence of any need for high-temperaturesterilisation renders less expensive forms of container, which would notsurvive the application of heat for sterilisation purposes, moreattractive. Plastics pots and other containers of plastics are thuspopular for aseptic packaging, particularly since they can readily besterilised immediately prior to being filled, the commonest method ofachieving such sterilisation being by treatment with hydrogen peroxidefollowed by a suitable brief heat treatment.

Aseptic packaging is normally carried out in a sterile atmosphere at apressure slightly above the prevailing ambient pressure, and istherefore performed in a suitable enclosed space. The process isaccordingly made as nearly fully automatic as possible, including ofcourse the operation of closing each filled container.

Thus, if the container components, such as container body and the endclosure member to be applied so as to seal the filled container, areeach pre-manufactured, the process of sterilising the components andfeeding them to the closing station of the packaging plant need normallypresent no particular difficulties.

End closure members for plastics pots used in aseptic packagingprocesses normally comprise a foil or other flexible diaphragm wherethere is no requirement for eventual opening of the container other thansimple removal of the closure. However, often the product is such thatthe consumer will expect to be able to gain access to the contents ofthe container without fully removing the end closure member, for examplewhere the contents are to be drunk direct from the container. It is nowusual in such cases to use a conventional metal can end of the so-called"easy opening" kind having a weakened portion which is removed bypulling on a metal pull tab or other similar device.

While a filled plastics pot with a metal easy-opening can endconstitutes a pack that is both technically satisfactory and attractivein appearance, it remains true that the metal can end is a relativelyexpensive component, and this must be reflected in the extent to whichthe use of aseptic packaging systems can be developed. As analternative, a conventional closure diaphragm can of course be provided,which must be removed fully before use. However, where there is arequirement that the container, filled with a beverage, should becapable of serving as a drinking vessel, such a conventional closure hastwo serious disadvantages. The diaphragm in these cases is sealed to therim of the container body by means of a peelable joint (obtained eitherby use of heat sealing or by employing a suitable peelable adhesive).Difficulties are sometimes encountered in achieving satisfactory orreliable peelable seals between components made from the materialscurrently favoured in aseptic packaging, this is particularly true ifthe seal area becomes contaminated with the product with which thecontainer is to be filled. In addition, when the diaphragm is removed bypeeling it away from the rim of the container body, a residue of heatsealing resin or adhesive is sometimes left on the rim. A furtherdisadvantageous possibility is that the rim may have a rough edge whichcan prove uncomfortable to the consumer drinking from the container.

According to the invention, in a first aspect, a container forfoodstuffs and beverages comprises a container body, at least the innersurface of which is of plastics material and having a rim defining amount of the body, and a lid comprising a diaphragm welded over thewhole of its periphery to the rim and covering the mouth of the body,the diaphragm having at least one through hole and a peel stripsealingly but peelably secured over the through hole or holes, the peelstrip having a pull tab.

Such a container thus has a lid which provides an alternative"easy-opening" end closure to the conventional metal kind, permitting abeverage to be drunk direct from the container without the need to peelthe whole diaphragm from the container body. By welding the lid to thebody, the other drawbacks of providing a peripheral peelable seal arealso avoided. It will be seen that the container according to theinvention is eminently suitable for use in aseptic packaging processes,and for containing products intended for drinking. However, thecontainer may contain foodstuffs other than beverages, and need not befilled or closed aseptically. One example of such other products is dry,particulate foodstuffs.

Preferably, the diaphragm and peel strip are each of laminatedconstruction having barrier properties substantially similar to those ofthe container body, whereby the container is hermetically sealed. Thediaphragm and peel strip would be of materials so formulated that thesurfaces presented to the contents of the container are acceptable underfood safety regulations for use with hydrogen peroxide sterilisationprocedures.

The peel strip may be in the form of a strip extending transverselyacross the diaphragm, preferably from one side to the other. As will beseen, this lends itself to a simple method of making the lid,particularly suitable in the automatic methods associated with asepticpackaging.

Preferably, the pull tab is located at an intermediate position on thepeel strip, the peel strip being secured to the diaphragm at the ends ofthe peel strip and at least locally of the through hole or holes. Thepeel strip may be otherwise unsecured to the diaphragm. Alternatively itmay be totally secured to the diaphragm.

The pull tab can most conveniently comprise a portion of the peel stripfolded back on itself, in which case the peel strip preferably has atransverse cut across part of its width at the junction of the pull tabwith the remainder of the peel strip on the side of the pull tab remotefrom said at least one through hole.

The diaphragm is preferably of laminated construction including an innerlayer of metal foil or a polymeric barrier material.

The peelable joint between the peel strip and the diaphragm may beobtained by use of a suitable adhesive, but preferably the diaphragm isof laminated construction including an outer layer of a lacquer heatsealed to the underside of the peel strip to form a sealable butpeelable interface. The peel strip is preferably also of laminatedconstruction including a barrier layer of metal foil or a polymericmaterial. A lower layer of the peel strip, adjacent the diaphragm, ispreferably of polymeric material. The materials of the laminations maybe such that all the lower layer of the peel strip is of polypropylene.

According to the invention, in a second aspect, a method of making asuccession of containers according to the invention includes theoperations of forming the through holes in a continuous web of thematerial for the diaphragms of the containers, applying peel stripmaterial to the said diaphragm material so as to obturate the throughholes, cutting each successive lid from the web, and welding eachsuccessive lid around the whole of its periphery to a filled containerbody.

Preferably the peel strip material is in the form of a continuous web,in the operation of applying it to the diaphragm material, is juxtaposedwith the web of diaphragm material so as to obturate the through holes.

The method preferably includes the step of heat sealing to the diaphragmmaterial at least those parts of the peel strip material that surroundthe hole or holes destined for each individual lid, prior to theoperation of cutting the respective lid from the web.

In addition, the method preferably includes the additional operation offorming each successive pull tab from the web of peel strip materialprior to the latter being applied to the web of diaphragm material. Thepreferred way of achieving this is that each pull tab is formed byfolding a portion of the web of peel strip material against itself andthen applying heat to the folded portion to bond together the two foldedhalves thereof, all with the web of peel strip material stationary.Preferably, the method includes the step of sterilising the webs afterthe peel strip material has been applied to the diaphragm material, sothat each lid is cut from sterilised material.

According to the invention, in a third aspect, apparatus for performingthe above method includes feed means for feeding the web of diaphragmmaterial and feed means for feeding the web of peel strip material intoaligned facial contact with each other at a peel strip applicationpoint, both of said feed means being operable in intermittent movementso as to allow a succession of dwell periods for operations on the webs,perforating means arranged for making the through hole or holes destinedfor each individual lid in the web of diaphragm material prior to eachperforated portion reaching the application point, and tab-forming meansarranged for forming each successive pull tab in the web of peel stripmaterial prior to the pull tab so formed reaching the application point.

An embodiment of the invention will now be described, by way of exampleonly, with reference to the drawings of this application, in which:

FIG. 1 is a perspective view of a container according to the invention,

FIG. 2 is a plan view of the same container,

FIG. 3 is an enlarged sectional elevation, taken on the line III--III inFIG. 2, and showing the lid of the container,

FIG. 4 is an enlarged scrap section through a pull tab of the container,

FIG. 5 is a greatly enlarged scrap section through a portion of the peelstrip of the container,

FIG. 6 is a similar view through a portion of the diaphragm,

FIG. 7 is a diagrammatic representation of part of a filling and closingapparatus using containers according to the invention,

FIG. 8 is a highly-simplified and somewhat diagrammatic side elevationof a machine for making a continuous strip of lidding material fromwhich the lids of the containers are subsequently cut,

FIGS. 9 to 13 show a part of the same apparatus, in five stages of theprocess of forming a pull tab for a said lid,

FIG. 14 is a much-enlarged detail taken from FIG. 13, and

FIG. 15 is a plan view on the above-mentioned continuous strip oflidding material at the place where a lid is cut from it.

Referring to FIGS. 1 to 4, the container shown in these Figurescomprises a container body 1 and a lid 2. The body 1 is a slightlydownwardly tapered pot or cup, having an open mouth at its top enddefined and surrounded by a rim 4, which in FIG. 3 is shown as anoutwardly directed curl or flange, but which may merely comprise a beador thickening of the end of the sidewall 6 of the cup. The containerbody 1 may be of any suitable material or combination of materials, butat least its inner surface 8 is of a plastics material. The cup 1 mayitself be entirely conventional, and made of a single plastics materialhaving sufficiently high gas barrier properties for the purpose of whichthe container is to be used. More usually it will be formed from sheetmaterial by a conventional thermoforming process, the sheet materialhaving at least two coextruded layers, one of the layers being of ahigh-barrier material such as one of the polymeric high-barriermaterials that are currently commercially available. Examples of suchmaterials are those sold under the trade marks SARAN and EVAL. Whateverform of construction, or materials, are used for the container body, itsinner surface 8 is of a plastics material suitable for being welded tothe underside of the lid 2. The inner surface 8 will thus typically beof the same material as the underside of the lid, and may for example beof low density polyethylene, high density polyethylene, orpolypropylene.

The lid 2 comprises a circular diaphragm 10 having two through holes,namely a relatively large pouring or drinking hole 12 and a smaller hole14 which serves as an air vent. Extending diametrically across thediaphragm 10, and extending from one side of the latter to the other, isa peel strip 16. The peel strip 16 covers the holes 12 and 14 and has apull tab 18 for the purpose of removing the strip so as to expose theholes. As will be seen, the peel strip is secured to the diaphragmsealingly, but can be readily peeled away from it when it is desired toopen the container.

Both the diaphragm 10 and the peel strip 16 are of laminatedconstruction, typically as illustrated in FIGS. 5 and 6. Referring tothese two Figures, the diaphragm 10 has a base or inner layer 20, anouter layer 24, and between the layers 20 and 24 a barrier layer 22. Theinner layer 20 is preferably of the same material as the inner surface 8of the container body 1, but is in any case of a material suitable to bewelded to the latter to form a fused hermetic seal. Subject to this, thelayer 20 and the inner-most layer of the cup 1 are of any suitablematerial or materials, such as polyolefins. Specific examples includelow density polyethylene, high density polyethylene, and polypropylene.These two layers are welded together by a fused heat seal bond aroundthe entire periphery of the rim 4 of the cup, as indicated at 26 in FIG.3. The barrier layer 22 of the diaphragm is for example of aluminiumfoil, but it may be of a polymeric material. Its outer layer 24 consistsof a thin coating of a protective lacquer which must be of a kindsuitable for allowing the peel strip 16 to be peelably but sealinglysecured to it. This lacquer must also be sufficiently resistant to heatnot to stick to the tooling which is used to form the welded peripheraljoint at 26 around the diaphragm. Suitable materials for the outer layer24 of the diaphragm include lacquers based on epoxy resin and satisfyingthe above criteria, and a lacquer which is based on a blend of an epoxyresin with a maleic anhydride modified polypropylene at a coat weight ofbetween 2 and 10 grams per square meter. An example of thislast-mentioned type of lacquer is that sold by Morton Chemical Limitedunder the Trade Mark MORPRIME 78 HB 76A.

The thickness of the inner layer 20 of the diaphragm is in the range 30to 100μ (0.03-0.1 mm) and is preferably 50 to 75μ (0.05-0.075 mm). Thealuminium foil barrier layer 22 has a thickness of 20-50μ (0.02-0.05mm), while the lacquer outer layer 24 is somewhat thinner than either ofthe other two layers.

The lamination structure of the peel strip 16 is somewhat different,though like that of the diaphragm, the lower or inner layer 28 is indirect contact (in this case through the holes 12 and 16 in thediaphragm) with the contents of the container. Both of the inner layers20 and 28 must therefore be of materials acceptable for use withfoodstuffs. In addition, the layer 28 and the upper layer 24 of thediaphragm must be capable of making at the interface a relaible hermeticseal which is also robust enough to withstand a certain amount of abusein handling and transport, yet which will permit the peel strip 16 to bereadily peeled away when it is time to open the container. At least withthe layer 24 of a lacquer such as those mentioned above, polypropyleneis the preferred material for the peel strip lower layer 28.

The peel strip 16 comprises the inner layer 28, a barrier layer 30, andan outer layer 32. The barrier layer 30 and outer layer 32 may be of anysuitable materials. In three non-limiting examples, they are,respectively of (a) aluminium foil and a polyester film, (b) thepolymeric barrier film material sold under the Trade Mark SARAN, and anylon, or (c) a barrier film material sold under the Trade Mark EVAL,and a nylon. The two last-mentioned cases are examples in which the peelstrip is transparent. Besides enhancing the appearance of the pack, theuse of a transparent peel strip enables the holes 12 and 14 to be seenwhile the container is still closed, thus making it easier for someconsumers to understand how to open it.

The thickness of the inner layer 28 of the peel strip at least if ofpolypropylene, is in the range 30-100μ (0.03-0.1 mm), i.e. similar tothat of the diaphragm inner layer 20. That of the barrier layer 30, ifof aluminium foil, is 9 to 40μ (0.009-0.4 mm) and preferably 9 to 20μ(0.009-0.2 mm), while the outer layer, if of polyester, has a typicalthickness of 12μ (0.012 mm).

The layers of the laminated materials may be bonded together using knownco-extrusion techniques, or by the use of conventional adhesives such asthose of polyurethane.

The criteria for peelability of the strip 16 from the diaphragm 10 areas stated above, and peel strength may be controlled, so as to satisfythese criteria, by selection of the correct blend of lacquer for theouter layer 24 of the diaphragm. For example, unmodified polypropylenemay be added to the basic lacquer in order to adjust its concentration.The lacquer of layer 24 is preferably applied as a coating from asuitable dispersion. Containers having a lid made from the laminatedmaterials given as specific examples above satisfy the requirements ofthe United States Food and Drug Administration for packaging which is tobe subjected to hydrogen peroxide sterilisation in an aseptic packagingprocess. The barrier layers 30 and 22 should be such as to have gasbarrier properties at least as great as those of the container body 1.

Reverting to FIGS. 1 to 4, the pull tab 18 is an integral part of thepeel strip 16. While it may be example be arranged at one end of thestrip 16, in this example the pull tab is located at an intermediateposition on the peel strip. The peelable seal between the strip 16 anddiaphragm 24 is not necessarily formed over the whole area of theformer, but may only be in the areas represented by broken hatching at36 and 38 in FIG. 2. These areas lie at the ends of the peel strip 16and in the area extending between the pull tab 18 and the end of thepeel strip nearest the hole 12, so that the region local to the throughholes 12 and 14, and surrounding them is totally sealed. There may thusbe a region, indicated at 34 in FIGS. 3 and 4, behind the pull tab, inwhich the peel strip 16 is unsecured to the diaphragm 10.

The pull tab 18 is formed simply by folding a portion of the peel stripmaterial back on itself. At the base of the pull tab, a transverse cut40 (FIG. 4) is made across part of the width of the pull tab, throughthe rearward one only of the two folded halves of the folded portion,i.e. through the right hand half only of the thickness of the pull tabas seen in FIG. 4. This establishes the direction in which the peelstrip is most easily removed.

When the container has been filled, and closed by welding the lid 2 tothe container body 1, the pull tab 18 lies flat over the region 34 or isinclined upwardly somewhat as indicated in FIGS. 1 and 4. To open thecontainer, the pull tab is gripped between finger and thumb, and pulled.Because of the cut 40, the direction in which the peel strip will tendto move most readily is as indicated in FIG. 3. The peel strip portion34 tends to lift and the pull tab 18 is hinged forwards so as first tobreak the peel strip 16 at the portion weakened by the cut 40, and thento peel the strip from over the holes 14 and 12. The user can then drinkfrom the hole 12.

Referring now to FIG. 7, this diagram crudely represents elements of anaseptic packaging line for packing a beverage, such as fruit juice in asuccession of containers of the kind described above with reference toFIGS. 1 to 6. The container bodies (pots) 1 are filled with juice at afilling station 50, whence they are conveyed to a closing station 52 byan intermittently-moving conveyor 54. If this equipment is part of aneseptic packing line, there will be, associated with the filling station50, apparatus (not shown) of a suitable known kind for sterilising thecontainers, there being also suitable means of a known kind forretaining the sterility at least up to a point downstream of the closingstation 52.

The movement of the conveyor 54 is synchronised with the action of thefilling apparatus (not shown) at the filling station 50, and with thatof the closing apparatus (not shown) at the closing station 52 at whichthe lid of each successive pot is welded to the latter in the manneralready described. Filling and closing take place when the conveyor isat rest. Also at the closing station 52, successive lids are cut from acontinuous cover strip 56, of lid material, which is advanced towardsand through the station 52 in synchronism with the movement of theconveyor 54. The closing apparatus may be of any conventional kindsuitable for cutting successive thin flexible diaphragm-type lids from acontinuous strip and applying them to close a container mouth withapplication of heat to effect a seal.

The continuous cover strip 56, as will be seen shortly, comprises a web58 of diaphragm material (for example as described with reference toFIG. 6) having the holes 12 and 14 (not seen in FIG. 7) and with,secured along it, a continuous web 60 of peel strip material with thepull tabs 28 already formed. The cover strip is advanced, pull tabs 18uppermost, via suitable means such as feed roller 62, from a cover stripforming machine 64. After leaving the forming machine 64, the strip 56is passed through a sterilising unit 63 (of any suitable known type), sothat the lids are then cut from sterilised material.

Reference is now made to FIG. 8, which shows the forming machine 64. Amachine frame 66 carries a diaphragm web spool 68 at the top, and a peelstrip web spool 70 at the bottom, these spools being carried on shaftsfreely-rotatable in the frame 66. Also carried by the machine frame area press tool 72, a horizontal main heat sealing anvil 74, and a mainheat sealing head 76 which is reciprocable vertically against the anvil74 by means of a main piston-and-cylinder actuator 78, carried by theframe 66. Carried by the piston of the actuator 78, besides the mainheat sealing head 76, is a tab sealing head 80, which lies below a pairof opposed anvils 82 and 84. The anvils 82 and 84 are carried byrespective anvil guides 86 and 88, which extend vertically to definebetween them a vertical gap, and which are fixed to the machine frame66. The anvils are resiliently mounted in the guides 86 and 88, forlimited vertical movement therein. Lying below the right-hand anvil 84,in FIG. 8, is a folding plate 90, which is reciprocable horizontally ina fixed slide 91 by a further actuator 92 carried by the frame 66. Thefolding plate 90 is so positioned as to be reciprocable between thetab-sealing head 80 and the anvils 82, 84 above it.

The purpose of the tab sealing head 80 is to cause the two folded halvesof each pull tab 18 to adhere to each other, as will be described. Thehead 80 comprises a heat-sealing unit 94 and a cutting block 96, andterminates in a guide block 98 which lies vertically below theright-hand anvil 84.

In operation, a coil 100 of the diaphragm web 58, and a coil 102 of thepeel strip web 60, are mounted on the respective spools 68 and 70. Thediaphragm web 58 extends from its coil over idler rollers 104 and into ahorizontal run 106 which extends through the press tool 72. The tool 72is of conventional construction, and operates to form the holes 12 and14 through the web 58. The run 106 continues to a point at which itmakes the peel strip web 60 on a guide roller 108, carried by the frame66 and freely rotatable.

The web 60 extends upwardly from its coil 102 to a reverse bend, whichis formed by the web bearing first on the guide block 98 and then on theright-hand anvil 84, from whence the web passes through the gap betweenthe anvil guides 86, 88 and over the guide roller 108. The horizontalrun 106, now comprising both webs, continues through the gap between themain anvil 74 and main heat-sealing head 76 and thence between a pair ofdrive rollers 110.

The rollers 110 are driven in intermittent rotation so as to draw thecover strip 56 forward, the coils 100 and 102 unwinding accordingly. Theactuators 78 and 92 and the press tool 72 are operated during thestationary periods. The indexing means by which the timing of theoperations of the various components is controlled is conventional andis not shown. It should be noted that, although preferably the forwardspeed of the cover strip 56 should be exactly the same on exit from thestrip forming machine 64 as on entering the closing station 52 (FIG. 7),it is not essential that the drive rollers 110 be linked or synchronisedwith the closing apparatus at the station 52. The cover strip may forexample be formed into a coil and stored for subsequent use at the sameor another site.

As the coil 102 of peel strip web unwinds, it continues to bear upon theguide block 98, as indicated by phantom lines in FIG. 8.

Referring now to all of FIGS. 8 to 13, one cycle of operation of thestrip forming machine 64 will now be described. At the commencement ofthe cycle the drive rollers 110, which have been indexing the coverstrip 56 forward, stop. The configuration is now as seen in FIGS. 8 and9, the actuators 78 and 92 being in their retracted positions as shown.The webs 58 and 60 now being at rest, the press tool 72 operates so asto form a through hole 12 and an adjacent hole 14 (FIG. 2) in thediaphragm web 58. At the same time, the actuator 92 is energised,driving the folding plate 90 forward as shown in FIG. 9. This forms abight 112 in the peel strip web 60, at the same time drawing a smallportion of the web 60 from the coil 102. The bight 112 lies in the gapbetween the heat seal unit 94 and the lefthand anvil 82.

The folding plate 90 is now withdrawn, leaving the bight 112 supportedbetween the anvil 82 and the tab sealing head 80 (FIG. 11). The mainactuator 78 is then operated. This drives the main heat sealing head 76upwardly to apply heat to the webs 58 and 60 against the main anvil 74.It should be noted that the head 76 is so configured that it appliesheat only over selected portions of the webs such as to heat seal thepeel strip web to the diaphragm web in those areas which, when that partof the cover strip 56 is later cut out to form a lid 2, will constitutethe areas required to be sealed, for example as seen in FIG. 2.

The operation of the main actuator 78 at the same time drives the tabsealing head 80 towards the two anvils 86 and 88, as shown in FIG. 12,the heat sealng unit 94 being simultaneously energised. The web 60 thusbecomes clamped between the guide block 98 and the right-hand anvil 84,while the bight 112 becomes tightly folded and clamped between the unit94 and the other anvil 86. The heat sealing unit 94 causes the twohalves of this folded portion to adhere together, thus forming a pulltab 18. At the same time the cutting blade 96 pierces the web 60, toform the cut 40 shown in FIGS. 2 and 4, in the exposed portion of theweb between its two clamped areas. To avoid damage to the web 60, theanvils 82 and 84 may retract upwardly by a small amount in their guides86 and 88 respectively.

Finally, the main actuator 76 is retracted so as to restore the machineto the conditions at the start of the cycle, whereupon the drive rollers110 begin to rotate again, drawing the webs forward (FIG. 13) by adistance equal to one pitch between successive lids. In FIG. 13, thepull tab the formation of which has just been described is indicated at18'.

In high-speed operation, cooling of the sealed tab may be required. Thismay be achieved by blowing cold air over it (by means not shown).

FIG. 14, in which the webs 58 and 60 are shown partly in section,illustrates the relative positions of a newly-formed pull tab 18 and theholes 12 and 14 as the two webs come into contact with each other on theroller 108 with the web 60 obturating the holes 12 and 14. Also shown inFIG. 14 is the manner in which the pull tab is folded back against thepeel strip web 60 as it passes over the roller 108, thus ensuring thatwhen it forms part of a lid 2, the pull tab is orientated correctly (asin FIG. 1) ready for use by the consumer.

The cover strip 56 made by the process described above is illustrated inFIG. 15. At the closing station 52 (FIG. 7), a lid 2 is punched from thestrip 56 over a filled container body 1 before being welded to thelatter, leaving a scrap portion of the cover strip, as at 114, to beremoved in any suitable manner.

We claim:
 1. A method of making a succession of food or beverage containers, each comprising a vessel having a mouth surrounded by a rim presenting an upper surface of plastics material, the method comprising filling each vessel in turn, feeding over the vessel a continuous composite web of lidding material produced by forming spaced apart perforations each comprising at least one through hole, in a continuous first web of diaphragm material having a plastics surface weldable to the vessel rim, forming spaced apart pull tabs in a continuous second web of peel strip material by folding each of a succession of portions of the second web against itself to form each said pull tab, and subsequently applying and peelably securing the second web, which is narrower than the first web, to the first web so as to obturate the perforations such that one said pull tab is situated adjacent each perforation, the tab remaining secured to the second web only at a junction on its one end, cutting through the two secured continuous webs to form a lid in which the peel strip material is substantially coextensive with the diaphragm material, and securing the lid by an endless peripheral weld to the upper surface of the rim, thereby closing the vessel.
 2. The method according to claim 1, comprising making a transverse cut across part of the width of the second web at the location of the junction of the pull tab with the remainder of the second web.
 3. The method according to claim 2, wherein the said steps of folding and of making a transverse cut are performed simultaneously.
 4. The method according to claim 1, comprising the step of heat sealing to the first web at least those parts of the second web that surround the perforations destined for each individual lid, prior to the operation of cutting the respective lid from the composite web.
 5. The method according to claim 1, comprising the step of sterilizing the composite web after the second web has been applied to the first web, so that the composite web is fed to the vessel in a substantially sterilized state.
 6. The method according to claim 1, wherein the vessel is filled and closed under substantially sterile conditions.
 7. The method according to claim 1, providing feed means for feeding the first web, and providing feed means for feeding the second web into aligned facial contact with each other at an application point, both of said feed means being operable in intermittent movement so as to allow a succession of dwell periods for operations on the webs, perforating means arranged for making the perforation to each perforated portion of the first web reaching the application point, and further tab-forming means arranged for forming each successive pull tab in the second web prior to the pull tab so formed reaching the application point.
 8. The method according to claim 7, wherein the tab-forming means includes further perforating means for making a transverse cut across part of the width of the second web at the location of the rearward junction of the pull tab with the remainder of the second web. 